Safety device for gas systems



Aug. 19, 1941. v 'H. WENDLAND 2,252,905

. 7 SAFETY DEVICE FOR GAS SYSTEMS Filed March 30 1939 3 J8 1 18 u 17 J8 J9 21-17 i226 5.2 N 22 i2 750 K 2548 Jo g 46 6 21 49 A 46 J2 I 23 4.3 43 r '1 .14 J3 34 t 39 38 J5- JJ 2 42 .23 22 47 ,Ihvenior:

I V vll-lo-froeys.

supply liquid.

' the latter completely in the event of the com- Patent'ed Aug. 19, 1941 "UNITED, STATES PATENT OFFI-(IE;

SAFETY DEVICE FQR GAS SYSTEMS Heinrich Wendland, Bnlstenbek, near Pinneberg, Germany Application March 30,119.39, Serial No. 264,960

' v In Germany September 5, 1938 ,8 Claims. (oi. ii -192) This invention relates to'means for safeguarding against return flow oi. explosive gas mixtures in gas pipes and against subsequent explosions by using a closing member and a movable control member influenced by the explosion pressure. The known arrangements of this type require,-in addition, water pockets or the like which constitute a. considerable source ot'danger because of the uncertainty of a sufllcient constant The object of the invention is to provide a dry-safety device which acts even when the flow or combustible gas stops preparing the closure of the closure valve member in order to. close flow in the gas pipe in orderto open the closure jvalve member. In this -way, by-using flexible membranes as the control member, the membrane disposed between'the' outflow side of the taneously keep the control membrane In. Between the flanges l2 and I3 of the housing parts 3 and 6 is arranged, as a control member, a control: membrane H which acts contrarily to the control member III, the flanges being connected together by bolts l5 which also hold the control membrane I4. A movable membrane I8, serving as a sealingmember, is disposed between the flanges l6 and I1 oi the housing parts 6 and l. The flanges l6 and ll 'of the sealing membrane l8 are held together by bolts |9. At the lower end of the housing part 6 there, is 7 arranged a movable membrane 2| which serves as a sealing member and which is fixed with the annular flange 22 and bolts 23 to the housing part6. Thehousingpart 6 contains the closing member 24 with a guiding and control spindle 25, which is arranged to slide longitudinallyin a passage 26 and bears on the sealing membrane being subjected to the pressure of the forward gas pipe and the closure valve member has a 30 greater efl'ective surface than the membrane disposed between the inflow side of the gas pipe and theclosure valve-member.

An embodiment of the invention is shown, by

way of example, in the drawinawherein:

Figure 1 is a section of the device partly in elevation showing it in the inoperative position.

Figure 2 is the same device in section during normal operation in a position of superintending and v Figure 3 is the same device with the closing member closed or blockedbeiore or during an explosion.

I is the housing, of the device which in the embodiment illustrated is made in four parts.

The pipe for the combustible gas is connected to the union 2 of the housing part 3 whereas the combustible gas pipe leading to the welding or cutting burner is connected to the union 4 of the housing part 5. The housing parts 6 and I are 1, disposed between the parts 3 and 5. A movsable control membrane lll is arranged as control member between the flanges 8 and 3 of the 1 r housing parts 5 and I. The flanges 3 and 3 y areoonnected' together by bolts II which simulin the union 45. In the vicinity of the bore 48 2|. The closing member 24 rests, with a washer 21, of rubber or the like and under the influence 01 a spring 28, resiliently on a valve seating 29. A protective cap 30 surrounds the spring 23, which bears against the upper covering wall of said cap and forces it in the raised position against the sealing membrane IS. A" spindle 3| carrying a plate. 32 abuts against the top of the sealing membrane I8 with the plate 32 bearing against Lhe underside oi'the controlmembrane ill. The spindle 3|, which is guided longitudinally in a passage'33 of the housing part 'I, is

formed with an annular recess 34 which can engage, under the influence of a spring 36, a locking rod 35 guided at right angles to the control spindle 3| in the housing part I. The looking rod 35 latched in the annular groove 34 can be pulled back. into the superintendingposition by a handle 31. A spindlet38 havinga plate 39 is arranged between control membrane I4 and the sealing membrane 2|, the upper end of said spindle passing through the annular flange 22 and bearing against the sealing membrane 2| whereas the plate 39 rests at the lower end on the control membrane I4. The space 40 underneath the control membrane I0 is connected by openings 4| to atmosphere and the space 42 above the control membrane i4 is also connected to atmosphere by openings 43. A con necting pipe 45 is detachably arranged between a lateral union 44 of the housing part 3 and a union 45 of the housing part 8, said pipe con necting the space 41 underneath the control membrane l4 with the passage 26 surrounding a the valve spindle 25 by way 01' the bore 48 the valve spindle 25 is formed with an annular recess 49 and, if necessary, with longitudinal grooves for connection with the valve member space 50 through the valve seating 29 when the closing member 24 is opened. A bore 5| in the union 52 and a coiled delay pipe 53 having many turns and a minimum length of about 6 m. leads from this chamber 50 to the union 54 of the housing part 5, to the bore 55 with which is connected a passage or tube 55. and the space 51 above the control membrane II. The space 51 is extended upwardly as far as the lateral union 4 to which is connected the tube or pipe lead-.

ing to the burner. The delay pipe is preferably arranged in one plane and in order to attain the necessary minimum length, is led in zig-zag windings and wound several times around its zigzag windings so that the device and the delay pipe can be flxed on a plate. The flanges 8, l6, l2 conveniently engage with an outer annular wall over the outer edges of the opposite flanges 3, l1. l3.

The operation of the safety device is as follows: In the inoperative position the individual parts assume the positions shown in Figure 1 in which the closing member 24 bears under the influence of the spring 25 on the valve seating 23 and is closed.

If the closure valveat the combustible gas generating plant connected with the union 2 or' at the welding, cutting or soldering burner conunion 45, its bore .48, theannular groove 49 of I the valve spindle 25 and the intermediate space between the latterand the passage 25 into the valve chamber 50. From here the combustible gas flows through the bore 5| in the union 52, the

delay pipe 53, the union 54, with the bore55 and the passage 55 into the chamber 51 and the control. membrane l0 and from heretowards the Y burner through the union 4 and the pipe con- -nected thereto. During normal working the individual parts of the safety device then assume the position shown in Figure 2 and the combustible gas flows in the direction of the arrow.

If the flow oi combustible gas is throttled or stops due to obstruction of the burner or of the ruptions, there takes place a return flow of oxygen in the combustible gas pipe and into the space 51 above the control membrane i0, then the downward flexing of the control membrane In and the pressure on the valve 24 are increased in the closing direction. If the control spindle 3| moves downwardly to such an extent that its annular groove 34 comesqopposite the blocking rod as, the rod as is forced byjthe spring as into the groove 34 and holds the spindle 3| in the position in which the valve 24 is closed. or the explosive gas mixture can therefore only penetrate as far as the valve chamber 50, which is separated by the closed valve 24 from the combustible gas pipe leading to the generating or storage container. Subsequently, if upon extinguishing of the gas flame at the burner nozzle and then re-lighting of the burner, the gas mixture in the supply pipe becomes ignited, the

piercing flame is stopped in the valve chamber 50. In this chamber 50, the counter-pressure spring 28 and'the valve 24 are protected from the flame.

by the cap 30. The closing and blocking of the valve 24 is thus efl'ected not by the explosion pressure produced by the flame striking back, but has already been effected by the slower flow of com bustlble gas in the direction of the burner slack ening orbeing stopped. In so far as this is not entirely sufllcient to close and block the valve 24, this preventive measure is brought about by the oxygen creeping back raising the pressure in the chamberv 51. The operator at the burner may, however, be already warned by the movement of the blocking rod 35, which can be seen from outside, so that he does not r-ignite the extinguished flame, by which the striking back of the piercing flame'is produced.

If the delay pipe 53 is of sufllcient-length, the certainty that the closing and blocking of the valve 24- will take place before the piercing flame reaches the valve chamber is further increased. After examining the burner and the pipe between the burner and the safety device, or by reduced pressure in ment shown and described may undergo numerbumer-nozzle, or for other reasons,- then the contrql membrane 15, which is made somewhat;

. larger than-the control membrane I4, is aflected by the pressure of the combustible gas and is caused to flex downwardly. Thus the spindle 3| with its plate 32 and the sealing membrane l5 are also moved or'flexed, respectively. in a downward direction and press on the cap 30 and the closing ,member 24 disposed underneath the latter.

' At the same time, the counter-pressure spring 25 also-becomes operative and presses ion the valve 24, partly because 01 the lowering contrary eflect of thepressure of the flow of combustible gas-and partly because of the pressure of the sealing membrane ,ll'from above, so that the spring -25 closes thevalve 24 moreand more. It now, due to the' blocked burner or other interous modifications in order to adapt it-to any particular use without departing from the scope of the invention. The controlling and sealing members l0, |5. '2| ,F|4;may also be made as tube membraneaj pistpnsu-orthe like. The closing,

de'd on its side facing the inflow side rni c tible gas with a larger eifective surface-1th e other side, inwhich casefthe spring 24 cc. be made stronger and the member 2-4 may device more sensitive'so that theclosing of the valve takes place mor promptly. I claim: i

.1. Safety devicefor gas systems against returnflow of explosivetgas mixtures in gas pipes and r againstsubsequent explosions comprising a clos-l ing member, two, rriovable control members arranged on opposites'ides of said closing member and operativelyconnected thereto, one of said control members being disposed between the in-- flow side of thev'alve device and the closing member, said control member being subjected to the forward flow pressure of the gas before said clos-. ing member and adapted to hold the closing The oxygen I turn flow of explosive vice and the closing member in the open position during the normal 1 condition of the gas system, the other control member being disposed'between the outflow side of the valvedevice and the closing member,

ing member, said control member being subjected to the forward flow pressure of the gas beforesaid closing member and adapted to hold the closing member in the open position during the normal condition of the gas system and the other control member being disposed between the outflow side of the valve device and the closingmember and made of a larger eflective surface than the other control member, adapted to close said closing member at the return flow of posite sides of said valve chamber between said valve chamber and said counterpressure chambers. 5. Safety device for gas systems against return flow of explosive gas mixtures in gas pipes and against subsequent explosion comprising a closing member, two movable control membranes arranged on opposite sides of said closing memexplosive gas mixtures or the subsequent explosion, a counter pressure spring between said closing member and the control membrane on the outflow side of the valve'device adapted to-influence said closing member yieldably in the closing direction.

3. Safety device for gas systems against return flow of explosive gas mixtures in gas pipes and against subsequent explosions comprising a closing member, two movable control members on opposite sides of said closing memberand operatively connected thereto, one of said control members being disposed between the inflow side of the valve, device and the closing member, said control memberbeing subjected to the. forward flow pressure of the gas before said closing member and adapted to hold the closing member in the open position during the normal condition of the gas system and the other control member being disposed between the outflow side of the valve device and the closing member and made of a larger effective surface than the other control member adapted to closesaid closing mem-, her at the return flow of explosive gas mixtures or the subsequent explosion, a counter pressure spring between said closing member and the control membrane on the outflow side of the valve device adapted to influence said closing member yieldably in the closing direction, and a cap or casing surrounding said spring adapted to protect said spring against the explosion heat from the outflow side of the valve device during explosion.

4. Safety device for gas systems against regas mixtures in gas pipes and against subsequent explosion comprising a closing member, two movable control membranes arranged on opposite sides of said closing memher and operativelyconnected thereto, one of said control. membranes being disposed between the outflow side of the valve device and the closing-member, the other control membrane being disposed between the member and subjected to the forward flow pressure of the gas, adapted to hold the closing member yieldingly in the open position during the normal condition of'the gas inflow side of the valve desystem, a counter pressure chamber'for eachv control membrane, a valve chamber for said closing member and flexible sealing members on opbranes and said closing ber for said closing member and flexible sealing said valve chamber members on opposite sides of said valve chamber, an annular groove in said interconnecting piece between the closing member and said control member on the outflow side of the valve device, a resiliently loaded locking stem cooperating with said annular groove when the closing member is closed.

6.'Safety device for gas systems against return flow of explosive gas mixtures in gas pipes and against subsequent explosion comprising a closing member, two movable control membranes.

arranged on'opposite sides of said closing member and operatively connected thereto, one of said control membranes being disposed between the outflow side of the valve device and the closing member the other control membrane being disposed between the inflow side of the valvev device and the closing member and subjected to the forward chamber for said closing member, flexible sealing members on the inflow and outflow side of said valve chamber, interconnecting pieces between said sealing member and said control membrane onthe outflow side and at opposite sides of said sealing member on the inflow side.

7. Safety device for gas systems against return flow of explosive gas mixtures in gas Pipes and against subsequent explosion comprising a closing member, two movable control membranes arranged on ber and operatively connected said control membranes being disposed between the outflow side of the valve device and the closing member, the other control membrane being disposed between the inflow side of the valve device and the closing member and subjected to the forward flow pressure of the gas, a valve chamber for said closing member, flexible sealing members on the inflow and outflow side of interconnecting pieces bemember and said control and against subsequent explosion comprising a casing, a valve chamber, a v

the gas. interflow pressure of the gas, a valve opposite sides of said closing memthereto, one of gas systems against rea pressure chamber at one side 0! each control member at' the inflow side and the outflow side of the, valve device, connecting pipes between each pressure chamber and said valve chamber.

the pipe between the pressure chamber on the outflow side and the valve chamber havinglrequent turns and a length of more than eighteen feet, interconnecting pieces between said seal.- ing member and said control member on the outflow side and on opposite sides of the seaiins 5 member at the inflow side 0! the valve chamber.

' HEINRICH WENDLAND. 

